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Simple relations from complex outflows: How the
No full textContext. The tight empirical M − σ relation between the mass of a supermassive black hole (SMBH) and the velocity dispersion of the host galaxy bulge is often interpreted as the result of self-regulation via active galactic nucleus (AGN) feedback. This picture is motivated by analytical and semi-analytical models in which momentum-driven AGN winds can expel the gas once the SMBH reaches a critical mass. However, these models typically assume idealised conditions: smooth gas distributions, spherical symmetry, and very efficient cooling of the shocked AGN wind. It is unclear whether this paradigm is applicable under more realistic conditions.
Aims. We checked whether AGN outflows can establish the M − σ relation in a multi-phase and turbulent galactic bulge subject to realistic radiative cooling while conserving the shocked AGN wind energy.
Methods. We ran a suite of purpose-built hydrodynamical simulations of AGN outflows in turbulent gas shells, covering a wide range of constant AGN luminosities. We tracked the outflow evolution over the course of ≥1 Myr. We analysed the effect of AGN outflow on the cold dense gas and SMBH feeding, estimating the luminosity threshold for removing most of the cold gas from the central regions.
Results. We find that AGNs with significantly sub-Eddington luminosities cannot suppress SMBH feeding, while luminosities exceeding ∼0.7 times Eddington clear out both the diffuse hot gas and the cold clumps, consistent with the momentum-driven outflow formalism. We also show that dense gas clusters are affected almost exclusively by the AGN wind momentum, while the shocked wind energy escapes through low-density channels and inflates large bubbles of diffuse gas.
Conclusions. Active galactic nucleus wind-driven energy-conserving feedback in a turbulent multi-phase medium affects the dense gas only via the wind momentum. Thus, the momentum-driven outflow paradigm is applicable for explaining the M − σ relation even in realistic systems
A systematic search for dormant galaxies at
No full textJWST has revealed a population of “dormant” galaxies at z > 5 that have recently halted their star formation and are characterized by weak emission lines and significant Balmer breaks. Until now, only four such galaxies have been reported at z > 5, three with low stellar masses, M* 1.4). We find 14 dormant galaxies with stellar masses ranging from 107.6 − 1010.5, revealing an intermediate-mass population. By construction, these 14 sources are located about 1 dex below the star-forming main sequence. Their star formation histories suggest that they halted star formation between 10 and 25 Myr before the time of observation which, according to models, is comparable with the timescales of internally regulated bursts driving a “breathing” mode of star formation. Our results show that ∼1% of the galaxies in the DJA are in a dormant phase of their star formation histories, and they span a wide stellar mass range. These galaxies can be empirically selected using only their spectral features in NIRSpec prism data
The chemical DNA of the Magellanic Clouds
No full textIn this study we investigate the chemical enrichment of the rapid neutron-capture process in the Small Magellanic Cloud (SMC). We measured the [Eu/Fe] abundance ratio of 209 giant stars that are confirmed members of the SMC, providing the first extensive dataset of Eu abundances in this galaxy across its full metallicity range, spanning more than 1.5 dex. We compared the Eu abundances with those of Mg and Ba to evaluate the efficiency of the r-process relative to α-capture and s-process nucleosynthesis. The SMC shows enhanced [Eu/Fe] values at all metallicities (comparable with the values measured in the Milky Way) and a clear decline as [Fe/H] increases (from approximately −1.75 dex to approximately −0.5 dex), which is consistent with the onset of Type Ia supernovae. In contrast, [Eu/Mg] is enhanced by about +0.5 dex at all [Fe/H] and thus significantly above the values observed in Milky Way stars, where [Eu/Mg] remains close to the solar value, reflecting comparable production of r-process and α-capture elements. Moreover, [Ba/Eu] increases with metallicity beginning at [Fe/H] ≈ −1.5 dex, namely at a lower metallicity with respect to the Milky Way, where [Ba/Eu] starts to increase around [Fe/H] ≈ −1 dex. Our findings suggest the SMC has a higher production of Eu (with respect to the α-elements) than the Milky Way, but it is still in line with what has been observed in other dwarf systems within the Local Group. We confirm that galaxies with star formation efficiencies lower than the Milky Way have a high [Eu/α], probably indicating stronger efficiency of the delayed sources of the r-process at low metallicities
Using design thinking in climate friendly entrepreneurship education to foster SDGs
No full textEntrepreneurship education is a crucial area of education to develop to support the achievement of the SDGs. Exploring various approaches and methods is crucial to making entrepreneurship education more responsive to global challenges, particularly those related to environmental and energy sustainability. Climate-friendly entrepreneurship education based on design thinking is a viable alternative learning medium for developing climate-friendly entrepreneurship because it encourages innovative problem-solving and addresses market needs while still maintaining environmental sustainability, providing social benefits, and generating financial returns
Adapting to climate change: Projections and strategies for the Progo River, Indonesia
No full textGlobal climate change is projected to be significant and long-lasting in the 21st century, driven by rising greenhouse gas emissions from human activities. Reliable projections are crucial for reducing negative impacts, assessing water balance, managing water resources, and preparing for extreme hydrological events. This study examines the Progo River in Daerah Istimewa Yogyakarta (DIY), Indonesia, which drains about 17,432 km2 and is essential for regional irrigation. Climate data from the World Bank Climate Change Knowledge Portal were analyzed, including projected daily maximum temperature (Tmax) for 1950-2100, climatology of the daily maximum temperature (Tmax) for 2020-2039, annual precipitation for 1950-2100, and climatology of monthly precipitation for 2020-2039. All datasets are derived from CMIP6 simulations. Results indicate that while precipitation patterns are expected to remain relatively stable, temperatures in DIY will rise in the coming decades. Higher temperatures may increase evaporation, raising drought risks. To address these challenges, authorities should prioritize adaptation strategies, including river and floodplain rehabilitation, restoration of riparian buffers, integrated surface and groundwater management, conservation agriculture, and drought early warning systems
Adaptive pathways for water scarcity: Lessons from smallholder agriculture
No full textConventional adaptation planning in sub-Saharan Africa often centres on irrigation infrastructure, external training, and standardised packages that overlook farmers' lived realities. This study employs a Choice Experiment (CE) within an adaptive capacity framework to identify how smallholder farmers in Malawi prioritise strategies in response to agricultural water stress. A Random Parameters Logit model (RPL) reveals a strong preference for socially embedded options, including inclusive participation platforms, farmer groups, finance for water saving practices, and climate-tolerant crop varieties, while infrastructure-heavy and authority-led interventions attract lower support. The highest valued attributes are combined into three farmer-centred pathways: Empowered Farmer-Led Adaptation, Resilient Livelihood Diversification, and Community-Based Resilience Support. By aligning design with labour-based Willingness to Participate (WTP), the study provides feasible, legitimate, and equity-sensitive options suited to smallholder contexts
Synergistic effects of mechanical milling and annealing on the microstructural evolution and hardness of Fe–C alloy powders
No full textFe-C alloys provide high strength and hardness, enabling broad use in structural, automotive, and tooling applications. This study examines the coupled effects of mechanical milling duration (4, 8, and 12 h) and annealing temperature (400, 500, and 600 °C) on the microstructural evolution, phase behavior, elemental distribution, and hardness of Fe-C powders. This study produces powders via high-energy ball milling and performs controlled annealing. It characterizes microstructures with optical microscopy and Scanning Electron Microscopy (SEM), maps elemental distributions by Energy Dispersive X-ray Spectroscopy (EDS), and evaluates hardness using Brinell Hardness Number (BHN). Prolonged milling (12 h) refined grains to the ultrafine regime, whereas annealing at 600 °C promoted grain coarsening and surface oxidation. EDS mapping indicated carbon segregation at 400 °C and oxygen enrichment at 600 °C, consistent with carbide formation and oxidation, respectively. Milling for 12 h followed by annealing at 400 °C produced the highest hardness (320 BHN) by promoting nanostructuring and dislocation strengthening. Overall, coordinated control of milling and annealing enables tunable microstructures and properties in Fe-C alloys, informing the design of automotive components, sintered gears, and metal-matrix composites
Spatial clustering of geosites and tourism objects in Kebumen UNESCO Global Geopark: A kernel density approach
No full textGeotourism serves as a catalyst for sustainable development in geoparks by linking conservation, education, and community-based economic growth. The Kebumen UNESCO Global Geopark in Central Java, Indonesia, possesses exceptional geodiversity and landscape diversity but remains underdeveloped in terms of spatially grounded geotourism planning. This study applies Kernel Density Estimation (KDE) to examine the spatial distribution and clustering of geosites and tourism objects, establishing a geospatial foundation for integrated geotourism development. Data were compiled from scientific publications and online platforms, and processed using GIS-based spatial analysis. The KDE results reveal four distinct spatial clusters, shaped by geological structure and tourism intensity. Among these, three form the core framework of Kebumen's geotourism identity: (1) the Northern Core Cluster, serving as the scientific and educational hub; (2) the Central Transitional Cluster, integrating cultural, artificial, and educational attractions; and (3) the Southern Coastal Cluster, representing the main nature-based and recreational tourism corridor. Supporting clusters in the peripheral plains indicates potential for community-driven and rural tourism initiatives. This spatial structure highlights the complementarity between geological and tourism assets, providing a basis for thematic differentiation, spatial integration, and balanced regional growth
Effect of Ambient Humidity on Thermal Sensation Using Seat Ventilation System
No full textThermal environments inside vehicles can be more extreme than those in buildings due to limited thermal insulation. During summer driving, cabin temperatures often exceed 40 °C, requiring prolonged HVAC operation to achieve thermal comfort. To improve cooling efficiency, seat ventilation systems have been introduced. These systems circulate air through small perforations in the seat to promote sweat evaporation and enhance body cooling. The effectiveness of this cooling depends not only on air temperature but also on humidity, since evaporation is driven by vapor pressure differences. This study investigates the relationship between air humidity and cooling performance in seat ventilation systems, with the goal of optimizing thermal comfort. Human participant experiments were conducted to measure skin temperatures at the back and waist and to record thermal sensation responses under varying conditions of air temperature and humidity. Humidity levels at the air outlet were also monitored. The results indicate that lower ambient humidity improves the cooling effect, as reflected by increased humidity at the system’s air outlet. However, if the humidity is too low, overcooling may occur, resulting in discomfort. These findings underscore the importance of carefully managing both airflow and humidity to maintain comfortable thermal conditions in vehicle cabins
Thermal environment and energy consumption in highly insulated houses: A study based on measurements and simulations
No full textEnhancing the insulation performance in residential buildings is essential to achieve a decarbonized society and protect occupants from cold indoor environments. While highly insulated houses are becoming more prevalent, their thermal environments are still not fully understood. To assess the thermal conditions of highly insulated houses and the effects of improved insulation, we conducted a measurement survey in six residences with insulation ratings exceeding Japan’s current standards for new houses. The energy consumption of these houses was analyzed using a Building Energy Simulation tool, and annual energy consumption data were also collected. The measurement survey revealed that the indoor temperature of highly insulated houses was significantly higher in summer and lower in winter under intermittent heating and cooling. Temperature fluctuations ranged from as low as 10°C in winter to as high as 34°C in summer. The breakdown of energy consumption based on simulation showed that the heating and cooling demand, as well as appliance energy usage, varied across households. The results of this study could be used to determine standards for future houses